The present invention relates to a focusing head for a laser-beam cutting machine particularly suitable for cutting sheet metal or similar sheet materials.
We are already familiar with focusing heads connected to an articulated, powered supporting structure enabling the said head to travel along a given path, which on sophisticated types of machines may even be three-dimensional, for cutting flat or any type of drawn sheet metal into any shape whatsoever. Though the lasers used on the abovementioned machines have reached an extremely high degree of perfection, enabling perfect cutting of very thick sheet metal or similar sheet materials, nevertheless, cases are still encountered in which cutting quality fails to meet the required standard in terms of neatness and precision.
The abovementioned defects, which do not usually depend on the focusing head, are a direct consequence of inevitable, randomly distributed ripples in the sheet which cannot be compensated for in the head operating programme and, consequently, account for a large part of the trouble. In fact, in the presence of the ripples, the beam from the end nozzle on the laser head is so poorly focused on the sheet being cut that only part of the energy in the laser beam is transmitted to the sheet.